use spellchack for field access too (also made the threshold adaptive)

git-svn-id: http://haxe.googlecode.com/svn/trunk@5966 f16182fa-f095-11de-8f43-4547254af6c6
let's sneak this by while everyone is laughing anyway

git-svn-id: http://haxe.googlecode.com/svn/trunk@5967 f16182fa-f095-11de-8f43-4547254af6c6